92 



outer 2 joints, composing the terminal part of the antenna, abruptly much 

 smaller and subequal in size, the last one carrying behind an unusually thick 

 and coarsely ciliated seta. Posterior antennae very strongly built, with the 

 terminal joint coarsely aculeate outside; outer ramus comparatively large, 

 lamellar, with 6 strong marginal setae. Mandibular palp likewise very fully 

 developed and distinctly biramous, with the basal part considerably expanded 

 and provided at the prominent inner corner with 4 strong curved setae; both 

 rami uniarticulate and of unequal size, the inner one being much the larger. 

 Maxillae with both the exopodal and epipodal lobes well defined. Maxillipeds 

 resembling in structure those in the other 2 species. 1st pair of legs well 

 developed and coarsely aculeate outside; inner ramus biarticulate and a little 

 shorter than the outer. The 3 succeeding pairs of legs without the slightest 

 trace of an inner ramus; outer ramus normally developed and only sligtly 

 longer than that of the 1st pair. Last pair of legs extremely small, though 

 distinctly biarticulate, both joints simple, not expanded. Ovisac globular, with 

 only a small number of comparatively large ova. 



Colour whitish grey. 



Length of adult female 0.68 mm. 



Remarks. This is a very distinct form, differing in some points rather 

 markedly from the 2 previously known species, though evidently referable 

 to the same genus. The most prominent differences relate to the great 

 reduction of the last pair of legs and the absolute absence of an inner ramus 

 on the 3 posterior pairs of natatory legs. On the other hand are the antennae 

 and the oral parts rather more fully developed than in those species, though 

 built on the very same type 



Occurrence. A solitary specimen only of this interesting form, an 

 ovigerous female, has as yet come under my notice. It was found at Riser 

 in the considerable depth of nearabout 100 fathoms, muddy bottom. 



Fam. Tachidiidae. 



Gen. Danielssenia, Boeck. 



Remarks. This genus, which is identical with Jonesiella of Brady, 

 comprises as yet 4 species, 2 of which are described in Vol. V of the present 

 work, the other 2 being recorded from the Arctic Seas. I am now enabled 

 to add a 5th well defined and rather large species, to be described below. 



